Long-Term Safety and Efficacy of Recombinant Human Parathyroid Hormone (1-84) in Adults With Chronic Hypoparathyroidism

Context

Chronic hypoparathyroidism is conventionally treated with oral calcium and active vitamin D to reach and maintain targeted serum calcium and phosphorus levels, but some patients remain inadequately controlled.

Objective

To assess long-term safety and efficacy of recombinant human parathyroid hormone (1-84) (rhPTH(1-84)) treatment.

Methods

This was an open-label extension study at 12 US centers. Adults (n = 49) with chronic hypoparathyroidism were included. The intervention was rhPTH(1-84) for 6 years. The main outcome measures were safety, biochemical measures, oral supplement doses, bone indices.

Results

Thirty-eight patients (77.6%) completed the study. Throughout 72 months, mean albumin-adjusted serum calcium was within 2.00 to 2.25 mmol/L (8.0-9.0 mg/dL). At baseline, 65% of patients with measurements (n = 24/37) were hypercalciuric; of these, 54% (n = 13/24) were normocalciuric at month 72. Mean serum phosphorus declined from 1.6 ± 0.19 mmol/L at baseline (n = 49) to 1.3 ± 0.20 mmol/L at month 72 (n = 36). Mean estimated glomerular filtration rate was stable. rhPTH(1-84)-related adverse events were reported in 51.0% of patients (n = 25/49); all but 1 event were mild/moderate in severity. Mean oral calcium supplementation reduced by 45% ± 113.6% and calcitriol by 74% ± 39.3%. Bone turnover markers declined by month 32 to a plateau above pretreatment values; only aminoterminal propeptide of type 1 collagen remained outside the reference range. Mean bone mineral density z score fell at one-third radius and was stable at other sites.

Conclusion

6 years of rhPTH(1-84) treatment was associated with sustained improvements in biochemical parameters, a reduction in the percentage of patients with hypercalciuria, stable renal function, and decreased supplement requirements. rhPTH(1-84) was well tolerated; no new safety signals were identified.

Abaloparatide: an anabolic treatment to reduce fracture risk in postmenopausal women with osteoporosis

OBJECTIVE

Fractures due to osteoporosis represent a serious burden on patients and healthcare systems. The objective of this review is to provide an overview of the anabolic agent abaloparatide (ABL) for the treatment of postmenopausal women with osteoporosis at high risk for fracture.

METHODS

A literature review was conducted using PubMed to identify articles focused on ABL published prior to February 10, 2020, using the search term "abaloparatide".

RESULTS

ABL, a synthetic analog of human parathyroid hormone-related protein, increased bone mineral density (BMD), improved bone microarchitecture, and increased bone strength in preclinical and clinical studies. The pivotal phase 3 trial ACTIVE and its extension (ACTIVExtend) demonstrated the efficacy of initial treatment with ABL for 18 months followed by sequential treatment with alendronate (ALN) for an additional 24 months to reduce the risk of vertebral, nonvertebral, clinical, and major osteoporotic fractures and to increase BMD in postmenopausal women with osteoporosis. Discontinuations from ACTIVE were slightly more common in ABL-treated patients due to dizziness, palpitations, nausea, and headache. Post hoc analyses of ACTIVE and ACTIVExtend support the efficacy and safety of ABL in relevant subpopulations including postmenopausal women with various baseline risk factors, women ≥80 years, women with type 2 diabetes mellitus, and women with renal impairment.

CONCLUSIONS

ABL is an effective and well-tolerated treatment for women with postmenopausal osteoporosis at high risk for fracture. Its therapeutic effects are sustained with subsequent ALN therapy.

Efficacy and safety of denosumab vs. bisphosphonates in postmenopausal women previously treated with oral bisphosphonates

Transitioning postmenopausal women with osteoporosis from a bisphosphonate to denosumab appears to be safe and more effective at improving BMD than continuing treatment with a bisphosphonate.

INTRODUCTION

We conducted a patient-level pooled analysis of four studies to estimate the efficacy and safety of transitioning to denosumab vs. continuing bisphosphonate treatment in postmenopausal women who previously received oral bisphosphonates.

METHODS

Patients received 60 mg denosumab once every 6 months or a bisphosphonate (oral alendronate, risedronate, ibandronate, or intravenous zoledronic acid). Endpoints were change from baseline in lumbar spine, total hip, femoral neck, and 1/3 radius BMD at month 12, change from baseline in serum CTX-1 and P1NP, and incidence of adverse events.

RESULTS

A total of 2850 randomized patients (1424 bisphosphonate:1426 denosumab) were included in the analysis. Percentage change in BMD was significantly greater (p < 0.001) for denosumab vs. bisphosphonate at each skeletal site; differences in BMD changes ranged from 0.6 to 2.0%. Percentage decrease in serum CTX-1 and P1NP was significantly greater (p < 0.0001) for denosumab vs. bisphosphonate at months 1, 6, and 12; in the denosumab group only, percentage change in serum CTX-1 at month 1 was significantly correlated with percentage change in lumbar spine and total hip BMD at month 12. The incidences of adverse events were similar between treatment groups. Three patients (one bisphosphonate and two denosumab) had atypical femoral fractures, all from the denosumab vs. zoledronic acid study.

CONCLUSION

Postmenopausal women can safely transition from a bisphosphonate to denosumab, which is more effective at improving BMD than continuing with a bisphosphonate.

CLINICAL TRIALS REGISTRATION

NCT00377819, NCT00919711, NCT00936897, NCT01732770.

Bone mineral density gains with a second 12-month course of romosozumab therapy following placebo or denosumab

Romosozumab is a therapy that stimulates bone formation and reduces bone resorption. In this study of postmenopausal women with low BMD, a second course of romosozumab following a period off treatment or on denosumab increased or maintained BMD, respectively, and was well tolerated, providing insight into treatment sequence options.

INTRODUCTION

In patients with high fracture risk, therapies that stimulate bone formation provide rapid BMD gains; currently available agents, parathyroid hormone receptor agonists, are limited to a 2-year lifetime exposure and generally used for a single treatment course. However, for long-term osteoporosis management, a second treatment course may be appropriate. Romosozumab, a therapy with the dual effect of increasing bone formation and decreasing bone resorption, reduces fracture risk within 12 months. Here, we report efficacy and safety of a second romosozumab course.

METHODS

In this phase 2, dose-finding study, postmenopausal women with low bone mass (T-score ≤ - 2.0 and ≥ - 3.5) received romosozumab or placebo (month 0-24) followed by placebo or denosumab (month 24-36); participants then received a year of romosozumab (month 36-48).

RESULTS

Of 167 participants who entered the month 36-48 period, 35 had been initially randomized to romosozumab 210 mg monthly. In participants who received romosozumab 210 mg monthly followed by placebo, a second romosozumab course (n = 19) increased BMD by amounts similar to their initial treatment (month 0-12) at the lumbar spine (12.4%; 12.0%, respectively) and total hip (6.0%; 5.5%, respectively). Following denosumab, a second romosozumab course (n = 16) increased BMD at the lumbar spine (2.3%) and maintained BMD at the total hip. Safety profiles were similar between first and second romosozumab courses.

CONCLUSIONS

After 12 months off-treatment, a second romosozumab course again led to rapid and large BMD gains. Following denosumab, BMD gains with romosozumab were smaller than with initial treatment. No new safety findings were observed during the second course.

The risk of subsequent osteoporotic fractures is decreased in subjects experiencing fracture while on denosumab: results from the FREEDOM and FREEDOM Extension studies

This post-hoc analysis queried whether women experiencing fracture on denosumab indicates inadequate treatment response or whether the risk of subsequent fracture remains low with continuing denosumab. Results showed that denosumab decreases the risk of subsequent fracture and fracture sustained while on denosumab is not necessarily indicative of inadequate treatment response.

INTRODUCTION

This analysis assessed whether a fracture sustained during denosumab therapy indicates inadequate treatment response and if the risk of a subsequent fracture decreases with continuing denosumab treatment.

METHODS

In FREEDOM, a clinical trial to evaluate the efficacy and safety of denosumab, postmenopausal women with osteoporosis were randomized to placebo or denosumab for 3 years. In the 7-year FREEDOM Extension, all participants were allocated to receive denosumab. Here we compare subsequent osteoporotic fracture rates between denosumab-treated subjects during FREEDOM or the Extension and placebo-treated subjects in FREEDOM.

RESULTS

During FREEDOM, 438 placebo- and 272 denosumab-treated subjects had an osteoporotic fracture. Exposure-adjusted subject incidence per 100 subject-years was lower for denosumab (6.7) vs placebo (10.1). Combining all subjects on denosumab from FREEDOM and the Extension for up to 10 years (combined denosumab), 794 (13.7%) had an osteoporotic fracture while on denosumab. Of these, one or more subsequent fractures occurred in 144 (18.1%) subjects, with an exposure-adjusted incidence of 5.8 per 100 subject-years, similar to FREEDOM denosumab (6.7 per 100 subject-years) and lower than FREEDOM placebo (10.1 per 100 subject-years). Adjusting for prior fracture, the risk of having a subsequent on-study osteoporotic fracture was lower in the combined denosumab group vs placebo (hazard ratio [95% CI]: 0.59 [0.43-0.81]; P = 0.0012).

CONCLUSIONS

These data demonstrate that denosumab decreases the risk of subsequent fracture and a fracture sustained while on denosumab is not necessarily indicative of inadequate treatment response.

Effects of 24 Months of Treatment With Romosozumab Followed by 12 Months of Denosumab or Placebo in Postmenopausal Women With Low Bone Mineral Density: A Randomized, Double-Blind, Phase 2, Parallel Group Study

Over 12 months, romosozumab increased bone formation and decreased bone resorption, resulting in increased bone mineral density (BMD) in postmenopausal women with low BMD (NCT00896532). Herein, we report the study extension evaluating 24 months of treatment with romosozumab, discontinuation of romosozumab, alendronate followed by romosozumab, and romosozumab followed by denosumab. Postmenopausal women aged 55 to 85 years with a lumbar spine (LS), total hip (TH), or femoral neck T-score ≤-2.0 and ≥-3.5 were enrolled and randomly assigned to placebo, one of five romosozumab regimens (70 mg, 140 mg, 210 mg monthly [QM]; 140 mg Q3M; 210 mg Q3M) for 24 months, or open-label alendronate for 12 months followed by romosozumab 140 mg QM for 12 months. Eligible participants were then rerandomized 1:1 within original treatment groups to placebo or denosumab 60 mg Q6M for an additional 12 months. Percentage change from baseline in BMD and bone turnover markers (BTMs) at months 24 and 36 and safety were evaluated. Of 364 participants initially randomized to romosozumab, placebo, or alendronate, 315 completed 24 months of treatment and 248 completed the extension. Romosozumab markedly increased LS and TH BMD through month 24, with largest gains observed with romosozumab 210 mg QM (LS = 15.1%; TH = 5.4%). Women receiving romosozumab who transitioned to denosumab continued to accrue BMD, whereas BMD returned toward pretreatment levels with placebo. With romosozumab 210 mg QM, bone formation marker P1NP initially increased after treatment initiation and gradually decreased to below baseline by month 12, remaining below baseline through month 24; bone resorption marker β-CTX rapidly decreased after treatment, remaining below baseline through month 24. Transition to denosumab further decreased both BTMs, whereas after transition to placebo, P1NP returned to baseline and β-CTX increased above baseline. Adverse events were balanced between treatment groups through month 36. These data suggest that treatment effects of romosozumab are reversible upon discontinuation and further augmented by denosumab. © 2018 The Authors Journal of Bone and Mineral Research published by Wiley Periodicals, Inc.

ACTIVExtend: 24 Months of Alendronate After 18 Months of Abaloparatide or Placebo for Postmenopausal Osteoporosis

PURPOSE

In women with postmenopausal osteoporosis, we investigated the effects of 24 months of treatment with alendronate (ALN) following 18 months of treatment with abaloparatide (ABL) or placebo (PBO).

METHODS

Women who completed ABL or PBO treatment in ACTIVE were eligible to receive up to 24 months of ALN. We evaluated the incidence of vertebral and nonvertebral fractures and changes in bone mineral density (BMD) during the entire 43-month period from ACTIVE baseline to the end of ACTIVExtend and for the 24-month extension only.

RESULTS

Five hundred fifty-eight women from ACTIVE's ABL group and 581 from its PBO group (92% of ABL and PBO completers) were enrolled. During the full 43-month treatment period, 0.9% of evaluable women in the ABL/ALN group experienced a new radiographic vertebral fracture vs 5.6% of women in the PBO/ALN group, an 84% relative risk reduction (RRR, P < 0.001). Kaplan-Meier incidence rates for other reported fracture types were significantly lower for ABL/ALN vs PBO/ALN (all P < 0.05). Gains in BMD achieved during ACTIVE were further increased during ACTIVExtend. For ACTIVExtend only, RRR for vertebral fractures was 87% with ABL/ALN vs PBO/ALN (P = 0.001). Adverse events were similar between groups. A supplemental analysis for regulatory authorities found no hip fractures in the ABL/ALN group vs five in the PBO/ALN group.

CONCLUSIONS

Eighteen months of ABL followed by 24 months of ALN reduced the risk of vertebral, nonvertebral, clinical, and major osteoporotic fractures and increased BMD. Sequential ABL followed by ALN appears to be an effective treatment option for postmenopausal women at risk for osteoporosis-related fractures.

Effect of denosumab on trabecular bone score in postmenopausal women with osteoporosis

Trabecular bone score (TBS) assesses bone quality in the lumbar spine using dual-energy X-ray absorptiometry (DXA) scans. In postmenopausal women with osteoporosis, denosumab significantly improved TBS independently of bone mineral density (BMD). This practical technique may have a role in managing patients with osteoporosis.

INTRODUCTION

TBS, a gray-level texture index determined from lumbar spine DXA scans, correlates with bone microarchitecture and enhances assessment of vertebral fracture risk independently of BMD. In the FREEDOM study, denosumab increased BMD and reduced new vertebral fractures in postmenopausal women with osteoporosis. This retrospective analysis explored the effect of denosumab on TBS and the association between TBS and BMD in FREEDOM.

METHODS

Postmenopausal women with lumbar spine or total hip BMD T-score <-2.5 and -4.0 or higher at both sites received placebo or denosumab 60 mg subcutaneously every 6 months. TBS indices were determined from DXA scans at baseline and months 12, 24, and 36 in a subset of 285 women (128 placebo, 157 denosumab) who had TBS values at baseline and ≥1 postbaseline visit.

RESULTS

Baseline characteristics were comparable between treatment groups; mean (SD) lumbar spine BMD T-score was -2.79 (0.64), and mean (standard deviation [SD]) TBS was 1.200 (0.101) overall. In the placebo group, BMD and TBS increased by ≤0.2% or decreased from baseline at each visit. In the denosumab group, progressive increases from baseline at 12, 24, and 36 months were observed for BMD (5.7, 7.8, and 9.8%) and TBS (1.4, 1.9, and 2.4%). Percentage changes in TBS were statistically significant compared with baseline (p < 0.001) and placebo (p ≤ 0.014). TBS was largely unrelated to BMD, regardless of treatment, either at baseline or for annual changes from baseline (all r ² ≤ 0.06).

CONCLUSIONS

In postmenopausal women with osteoporosis, denosumab significantly improved TBS independently of BMD.

10 years of denosumab treatment in postmenopausal women with osteoporosis: results from the phase 3 randomised FREEDOM trial and open-label extension

BACKGROUND

Long-term safety and efficacy of osteoporosis treatment are important because of the chronic nature of the disease. We aimed to assess the long-term safety and efficacy of denosumab, which is widely used for the treatment of postmenopausal women with osteoporosis.

METHODS

In the multicentre, randomised, double-blind, placebo-controlled, phase 3 FREEDOM trial, postmenopausal women aged 60-90 years with osteoporosis were enrolled in 214 centres in North America, Europe, Latin America, and Australasia and were randomly assigned (1:1) to receive 60 mg subcutaneous denosumab or placebo every 6 months for 3 years. All participants who completed the FREEDOM trial without discontinuing treatment or missing more than one dose of investigational product were eligible to enrol in the open-label, 7-year extension, in which all participants received denosumab. The data represent up to 10 years of denosumab exposure for women who received 3 years of denosumab in FREEDOM and continued in the extension (long-term group), and up to 7 years for women who received 3 years of placebo and transitioned to denosumab in the extension (crossover group). The primary outcome was safety monitoring, comprising assessments of adverse event incidence and serious adverse event incidence, changes in safety laboratory analytes (ie, serum chemistry and haematology), and participant incidence of denosumab antibody formation. Secondary outcomes included new vertebral, hip, and non-vertebral fractures as well as bone mineral density (BMD) at the lumbar spine, total hip, femoral neck, and one-third radius. Analyses were done according to the randomised FREEDOM treatment assignments. All participants who received at least one dose of investigational product in FREEDOM or the extension were included in the combined safety analyses. All participants who enrolled in the extension with observed data were included in the efficacy analyses. The FREEDOM trial (NCT00089791) and its extension (NCT00523341) are both registered with ClinicalTrials.gov.

FINDINGS

Between Aug 3, 2004, and June 1, 2005, 7808 women were enrolled in the FREEDOM study. 5928 (76%) women were eligible for enrolment in the extension, and of these, 4550 (77%) were enrolled (2343 long-term, 2207 crossover) between Aug 7, 2007, and June 20, 2008. 2626 women (1343 long-term; 1283 crossover) completed the extension. The yearly exposure-adjusted participant incidence of adverse events for all individuals receiving denosumab decreased from 165·3 to 95·9 per 100 participant-years over the course of 10 years. Serious adverse event rates were generally stable over time, varying between 11·5 and 14·4 per 100 participant-years. One atypical femoral fracture occurred in each group during the extension. Seven cases of osteonecrosis of the jaw were reported in the long-term group and six cases in the crossover group. The yearly incidence of new vertebral fractures (ranging from 0·90% to 1·86%) and non-vertebral fractures (ranging from 0·84% to 2·55%) remained low during the extension, similar to rates observed in the denosumab group during the first three years of the FREEDOM study, and lower than rates projected for a virtual long-term placebo cohort. In the long-term group, BMD increased from FREEDOM baseline by 21·7% at the lumbar spine, 9·2% at total hip, 9·0% at femoral neck, and 2·7% at the one-third radius. In the crossover group, BMD increased from extension baseline by 16·5% at the lumbar spine, 7·4% at total hip, 7·1% at femoral neck, and 2·3% at one-third radius.

INTERPRETATION

Denosumab treatment for up to 10 years was associated with low rates of adverse events, low fracture incidence compared with that observed during the original trial, and continued increases in BMD without plateau.

FUNDING

Amgen.

Safety Observations With 3 Years of Denosumab Exposure: Comparison Between Subjects Who Received Denosumab During the Randomized FREEDOM Trial and Subjects Who Crossed Over to Denosumab During the FREEDOM Extension

Denosumab is a fully human monoclonal antibody against receptor activator of NF-κB ligand (RANKL) that decreases osteoclast formation, function and survival, and is approved for the treatment of postmenopausal women with osteoporosis at increased or high risk for fracture, among other indications. During the pivotal 3-year fracture trial FREEDOM, denosumab 60 mg subcutaneously every 6 months significantly reduced new vertebral (68%), hip (40%), and nonvertebral (20%) fractures; increased bone mineral density (BMD); and reduced bone turnover markers compared with placebo in postmenopausal women with osteoporosis. Questions have arisen regarding imbalances of certain low-frequency adverse events (AEs) observed in FREEDOM, as well as the top 5 most frequent adverse reactions listed in the United States prescribing information (USPI; back pain, pain in extremity, musculoskeletal pain, hypercholesterolemia, and cystitis). We examined the incidences of these AEs in women who originally received placebo during FREEDOM and then received denosumab for up to 3 years during the FREEDOM Extension (Crossover Group). This provided a unique opportunity for comparison with the original 3-year denosumab FREEDOM observations. We also examined the incidences of these AEs over 6 years of denosumab treatment (Long-term Group; ie, comparing a second 3 years of treatment with findings in the first 3 years). There was no indication of increasing trends regarding the imbalances of either low-frequency AEs or common AEs observed in FREEDOM. © 2017 American Society for Bone and Mineral Research.

Pharmacokinetics of coadministration of levothyroxine sodium and alendronate sodium new effervescent formulation

No clinically important pharmacokinetic interference of alendronate occurred between a new effervescent formulation of alendronate and levothyroxine when coadministered. The combination does not materially affect levothyroxine absorption.

INTRODUCTION

Concurrent treatment of osteoporosis with alendronate (Aln) and hypothyroidism with levothyroxine (LT4) may be problematic because both drugs are to be taken separately after fasting overnight. The primary objective was to assess pharmacokinetic interactions between a new effervescent formulation of Aln (Aln-NEF) and LT4.

METHODS

A randomized, open-label, 3-way crossover study was conducted in 30 healthy adults (15 women). Subjects were dosed 3 times, separated by 35 days, after overnight fasts, with Aln-NEF alone (70 mg), LT4 alone (600 μg), or Aln-NEF and LT4 concurrently. Samples were analyzed for plasma Aln and serum LT4. Pharmacokinetic drug-drug interaction was assessed using 90% confidence intervals (CIs) for the test/reference ratio of the geometric means for area under the concentration-time curve from time zero to last measureable time point (AUC_0-t ) and maximum concentration (C _max). Results were compared to the default no-effect boundaries of 80 to 125% for the ratio Aln-NEF and LT4 concurrently/Aln-NEF alone and the ratio Aln-NEF and LT4 concurrently/LT4 alone.

RESULTS

Geometric mean ratios (Aln-NEF with LT4/Aln-NEF alone) were 0.927 (90% CI 0.795-1.081) for AUC_0-8 and 0.912 (90% CI 0.773-1.077) for C _max, demonstrating LT4 does not appreciably affect the pharmacokinetics of Aln. Geometric mean ratios (LT4 with Aln-NEF/LT4 alone) were 1.049 (90% CI 0.983-1.119) for AUC_0-48 and 1.075 (90% CI 1.006-1.148) for C _max, demonstrating LT4 is bioequivalent between the 2 treatments. Coadministration of Aln-NEF and LT4 was well tolerated.

CONCLUSIONS

There was no clinically important pharmacokinetic interference between the Aln-NEF formulation and LT4. Aln-NEF does not materially affect LT4 absorption.

Influence of subject discontinuation on long-term nonvertebral fracture rate in the denosumab FREEDOM Extension study

Background

Denosumab treatment for up to 8 years in the FREEDOM study and Extension was associated with low fracture incidence. It was not clear whether subjects who discontinued during the study conduct had a higher risk of fracture than those who remained enrolled, thereby underestimating the true fracture risk for the entire trial cohort. Thus, we explored the influence of early withdrawals on nonvertebral fracture incidence during the Extension study.

Methods

To understand the potential effect of depletion of susceptible subjects on fracture incidence, we first evaluated subject characteristics in patients who were enrolled in the Extension vs those who were not. We subsequently employed a Kaplan-Meier multiple imputation (KMMI) approach to consider subjects who discontinued as if they remained enrolled with a 0%, 20%, 50%, and 100% increase in fracture risk compared with participants remaining on study.

Results

Extension enrollees were generally similar to nonparticipants in median age (71.9 and 73.1 years, respectively), mean total hip bone mineral density T-score (–1.9 and –2.0, respectively), and probability of fracture risk by Fracture Risk Assessment Tool (FRAX^®) at FREEDOM baseline (16.9% and 17.7% for major osteoporotic fracture and 6.7% and 7.4% for hip fracture, respectively). When we assumed a doubled fracture risk (100% increase) after discontinuation in KMMI analyses, nonvertebral fracture rate estimates were only marginally higher than the observed rates for both the crossover group (10.32% vs 9.16%, respectively) and the long-term group (7.63% vs 6.63%, respectively).

Conclusion

The observation of continued denosumab efficacy over 8 years of treatment was robust and does not seem to be explained by depletion of susceptible subjects.

Trial registration

ClincalTrials.gov registration number NCT00523341; registered August 30, 2007

Electronic supplementary material

The online version of this article (doi:10.1186/s12891-017-1520-6) contains supplementary material, which is available to authorized users.

Denosumab or Zoledronic Acid in Postmenopausal Women With Osteoporosis Previously Treated With Oral Bisphosphonates

CONTEXT

Denosumab and zoledronic acid (ZOL) are parenteral treatments for patients with osteoporosis.

OBJECTIVE

The objective of the study was to compare the effect of transitioning from oral bisphosphonates to denosumab or ZOL on bone mineral density (BMD) and bone turnover.

DESIGN AND SETTING

This was an international, multicenter, randomized, double-blind trial.

PARTICIPANTS

A total of 643 postmenopausal women with osteoporosis previously treated with oral bisphosphonates participated in the study.

INTERVENTIONS

Subjects were randomized 1:1 to sc denosumab 60 mg every 6 months plus iv placebo once or ZOL 5 mg iv once plus sc placebo every 6 months for 12 months.

MAIN OUTCOME MEASURES

Changes in BMD and bone turnover markers were measured.

RESULTS

BMD change from baseline at month 12 was significantly greater with denosumab compared with ZOL at the lumbar spine (primary end point; 3.2% vs 1.1%; P < .0001), total hip (1.9% vs 0.6%; P < .0001), femoral neck (1.2% vs -0.1%; P < .0001), and one-third radius (0.6% vs 0.0%; P < .05). The median decrease from baseline was greater with denosumab than ZOL for serum C-telopeptide of type 1 collagen at all time points after day 10 and for serum procollagen type 1 N-terminal propeptide at month 1 and at all time points after month 3 (all P < .05). Median percentage changes from baseline in serum intact PTH were significantly greater at months 3 and 9 with denosumab compared with ZOL (all P < .05). Adverse events were similar between groups. Three events consistent with the definition of atypical femoral fracture were observed (two denosumab and one ZOL).

CONCLUSIONS

In postmenopausal women with osteoporosis previously treated with oral bisphosphonates, denosumab was associated with greater BMD increases at all measured skeletal sites and greater inhibition of bone remodeling compared with ZOL.

The effect of 8 or 5 years of denosumab treatment in postmenopausal women with osteoporosis: results from the FREEDOM Extension study

The FREEDOM study and its Extension provide long-term information about the effects of denosumab for the treatment of postmenopausal osteoporosis. Treatment for up to 8 years was associated with persistent reduction of bone turnover, continued increases in bone mineral density, low fracture incidence, and a favorable benefit/risk profile.

INTRODUCTION

This study aims to report the results through year 5 of the FREEDOM Extension study, representing up to 8 years of continued denosumab treatment in postmenopausal women with osteoporosis.

METHODS

Women who completed the 3-year FREEDOM study were eligible to enter the 7-year open-label FREEDOM Extension in which all participants are scheduled to receive denosumab, since placebo assignment was discontinued for ethical reasons. A total of 4550 women enrolled in the Extension (2343 long-term; 2207 cross-over). In this analysis, women in the long-term and cross-over groups received denosumab for up to 8 and 5 years, respectively.

RESULTS

Throughout the Extension, sustained reduction of bone turnover markers (BTMs) was observed in both groups. In the long-term group, mean bone mineral density (BMD) continued to increase significantly at each time point measured, for cumulative 8-year gains of 18.4 and 8.3 % at the lumbar spine and total hip, respectively. In the cross-over group, mean BMD increased significantly from the Extension baseline for 5-year cumulative gains of 13.1 and 6.2 % at the lumbar spine and total hip, respectively. The yearly incidence of new vertebral and nonvertebral fractures remained low in both groups. The incidence of adverse and serious adverse events did not increase over time. Through Extension year 5, eight events of osteonecrosis of the jaw and two events of atypical femoral fracture were confirmed.

CONCLUSIONS

Denosumab treatment for up to 8 years was associated with persistent reductions of BTMs, continued BMD gains, low fracture incidence, and a consistent safety profile.

Effect of zoledronic acid on serum calcium in Paget's disease patients after educational strategies to improve calcium and vitamin D supplementation

OBJECTIVE

Bisphosphonates are the most effective therapeutic agents in patients with Paget's disease of bone. As a result of their inhibition of osteoclastic activity, hypocalcemia of variable frequency and severity following intravenous bisphosphonate therapy has been reported. The present study assessed the effect of physician and patient education on adequate supplementation of calcium and vitamin D to reduce the potential risk of developing hypocalcemia following infusion of 5 mg zoledronic acid.

METHODS

This was an open-label, multicenter, controlled registry trial in which patients with Paget's disease were treated with a single intravenous infusion of zoledronic acid. Physicians were provided with educational materials focusing on optimization of calcium and vitamin D supplementation following zoledronic infusion that they used to educate their patients. The primary safety variable was the percentage of patients with serum calcium level <2.07mmol/l 9-11 days after zoledronic acid infusion.

RESULTS

A total of 75 patients were evaluable in the post dose hypocalcemia safety analysis. Of these, only 1 patient had treatment-emergent hypocalcemia, with a serum calcium level of 1.92 mmol/l 4 days following therapy. Hypocalcemia-related symptoms were not reported in this patient and the serum calcium returned to normal range at 2.17 mmol/l within 1 week on oral calcium supplementation.

CONCLUSIONS

These results suggest that, with optimization of calcium and vitamin D supplementation by physician and patient education, hypocalcemia is an infrequent occurrence following zoledronic acid infusion.

Hypocalcaemia in patients with metastatic bone disease treated with denosumab

BACKGROUND

This analysis was performed to further characterise treatment-emergent hypocalcaemia in patients with bone metastases receiving denosumab.

METHODS

Laboratory abnormalities and adverse events of hypocalcaemia in patients with metastatic bone disease were analysed using data from three identically designed phase 3 trials of subcutaneous denosumab 120 mg (n = 2841) versus intravenous zoledronic acid 4 mg (n = 2836).

RESULTS

The overall incidence of laboratory events of hypocalcaemia grade ⩾ 2 was higher with denosumab (12.4%) than with zoledronic acid (5.3%). Hypocalcaemia events were primarily grade 2 in severity and usually occurred within the first 6 months of treatment. Patients who reported taking calcium and/or vitamin D supplements had a lower incidence of hypocalcaemia. Prostate cancer or small-cell lung cancer, reduced creatinine clearance and higher baseline bone turnover markers of urinary N-telopeptide of type I collagen (uNTx; > 50 versus ⩽ 50 nmol/mmol) and bone-specific alkaline phosphatase (BSAP; > 20.77 μg/L [median] versus ⩽ 20.77 μg/L) values were important risk factors for developing hypocalcaemia. The risk associated with increased baseline BSAP levels was greater among patients who had > 2 bone metastases at baseline versus those with ⩽ 2 bone metastases at baseline.

CONCLUSION

Hypocalcaemia was more frequent with denosumab versus zoledronic acid, consistent with denosumab's greater antiresorptive effect. Low serum calcium levels and potential vitamin D deficiency should be corrected before initiating treatment with a potent osteoclast inhibitor, and corrected serum calcium levels should be monitored during treatment. Adequate calcium and vitamin D intake appears to substantially reduce the risk of hypocalcaemia.

A 24-month study evaluating the efficacy and safety of denosumab for the treatment of men with low bone mineral density: results from the ADAMO trial

CONTEXT

One in 4 men in the United States aged >50 years will have an osteoporosis-related fracture. Fewer data are available on osteoporosis treatment in men than in women.

OBJECTIVE

The purpose of this study was to evaluate denosumab therapy in men with low bone mineral density (BMD).

DESIGN

This was a phase 3 study with 2 treatment periods: a previously reported 12-month double-blind, placebo-controlled phase and a 12-month open-label phase.

SETTING

This was a multicenter study conducted in North America and Europe.

PARTICIPANTS

A total of 228 men entered the open-label phase and 219 completed the study.

INTERVENTION

Men from the original denosumab (long-term) and placebo (crossover) groups received 60 mg of denosumab sc every 6 months.

MAIN OUTCOME MEASURES

BMD, serum collagen type I C-telopeptide, and safety were measured.

RESULTS

During the open-label phase, continued BMD increases occurred with long-term denosumab treatment (2.2% lumbar spine, 0.9% total hip, 1.3% femoral neck, 1.3% trochanter, and 0.2% 1/3 radius), resulting in cumulative 24-month gains from baseline of 8.0%, 3.4%, 3.4%, 4.6%, and 0.7%, respectively (all P < .01). The crossover group showed BMD gains after 12 months of denosumab treatment similar to those of the long-term denosumab group during the first treatment year. Significant reductions in serum collagen type I C-teleopeptide were observed after denosumab administration. Adverse event rates were similar between groups, and no new safety signals were identified.

CONCLUSIONS

In men with low BMD, denosumab treatment for a second year continued to increase BMD, maintained reductions in bone resorption, and was well tolerated. BMD increased in men initiating denosumab during the second year. These effects were similar to those previously seen in postmenopausal women with osteoporosis and in men with prostate cancer receiving androgen deprivation therapy.

Odanacatib for the treatment of postmenopausal osteoporosis: development history and design and participant characteristics of LOFT, the Long-Term Odanacatib Fracture Trial

SUMMARY

Odanacatib is a cathepsin K inhibitor investigated for the treatment of postmenopausal osteoporosis. Phase 2 data indicate that 50 mg once weekly inhibits bone resorption and increases bone mineral density, with only a transient decrease in bone formation. We describe the background, design and participant characteristics for the phase 3 registration trial.

INTRODUCTION

Odanacatib (ODN) is a selective cathepsin K inhibitor being evaluated for the treatment of osteoporosis. In a phase 2 trial, ODN 50 mg once weekly reduced bone resorption while preserving bone formation and progressively increased BMD over 5 years. We describe the phase III Long-Term ODN Fracture Trial (LOFT), an event-driven, randomized, blinded placebo-controlled trial, with preplanned interim analyses to permit early termination if significant fracture risk reduction was demonstrated. An extension was planned, with participants remaining on their randomized treatment for up to 5 years, then transitioning to open-label ODN.

METHODS

The three primary outcomes were radiologically determined vertebral, hip, and clinical non-vertebral fractures. Secondary end points included clinical vertebral fractures, BMD, bone turnover markers, and safety and tolerability, including bone histology. Participants were women, 65 years or older, with a BMD T-score≤-2.5 at the total hip (TH) or femoral neck (FN) or with a prior radiographic vertebral fracture and a T-score≤-1.5 at the TH or FN. They were randomized to ODN or placebo tablets. All received weekly vitamin D3 (5600 international units (IU)) and daily calcium supplements as needed to ensure a daily intake of approximately 1200 mg.

RESULTS

Altogether, 16,713 participants were randomized at 387 centers. After a planned interim analysis, an independent data monitoring committee recommended that the study be stopped early due to robust efficacy and a favorable benefit/risk profile. Following the base study closeout, 8256 participants entered the study extension.

CONCLUSIONS

This report details the background and study design of this fracture end point trial and describes the baseline characteristics of its participants.

Paget's disease of bone: an endocrine society clinical practice guideline

OBJECTIVE

The aim of this guideline was to formulate practice guidelines for the diagnosis and treatment of Paget's disease of the bone.

PARTICIPANTS

The guideline was developed by an Endocrine Society-appointed Task Force of experts, a methodologist, and a medical writer.

EVIDENCE

This evidence-based guideline was developed using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system to describe both the strength of recommendations and the quality of evidence.

CONSENSUS PROCESS

One group meeting, several conference calls, and e-mail communications enabled consensus. Committees and members of The Endocrine Society and the European Society of Endocrinology reviewed and commented on preliminary drafts of these guidelines. Two systematic reviews were conducted to summarize supporting evidence.

CONCLUSIONS

We recommend that plain radiographs be obtained of the pertinent regions of the skeleton in patients with suspected Paget's disease. If the diagnosis is confirmed, we suggest that a radionucleotide bone scan be done to determine the extent of the disease. After diagnosis of Paget's disease, we recommend measurement of serum total alkaline phosphatase or, when warranted, a more specific marker of bone formation or bone resorption to assess the response to treatment or evolution of the disease in untreated patients. We suggest treatment with a bisphosphonate for most patients with active Paget's disease who are at risk for future complications. We suggest a single 5-mg dose of iv zoledronate as the treatment of choice in patients who have no contraindication. In patients with monostotic disease who have a normal serum total alkaline phosphatase, we suggest that a specific marker of bone formation and bone resorption be measured, although these may still be normal. Serial radionuclide bone scans may determine the response to treatment if the markers are normal. We suggest that bisphosphonate treatment may be effective in preventing or slowing the progress of hearing loss and osteoarthritis in joints adjacent to Paget's disease and may reverse paraplegia associated with spinal Paget's disease. We suggest treatment with a bisphosphonate before surgery on pagetic bone.

Denosumab significantly increases bone mineral density and reduces bone turnover compared with monthly oral ibandronate and risedronate in postmenopausal women who remained at higher risk for fracture despite previous suboptimal treatment with an oral bisphosphonate

Managing osteoporotic patients suboptimally adherent to bisphosphonates (BPs) is difficult. Such patients who remained at higher risk for fracture (≥1 risk factor) were transitioned to denosumab or a monthly oral BP. Denosumab-treated subjects had significantly greater increases in bone mineral density and decreases in bone turnover in this 12-month study.

INTRODUCTION

A clinical need exists to manage patients who are suboptimally adherent to oral BPs and remain at higher risk for fracture. Here, we compare the effects on bone mineral density (BMD) and bone turnover of transitioning such patients to denosumab or monthly oral BP (ibandronate or risedronate).

METHODS

In two previous multicenter, open-label studies, postmenopausal women ≥55 years previously treated with, though suboptimally adherent to, a daily or weekly BP were randomized to denosumab 60 mg subcutaneously every 6 months (N = 852) or oral BP 150 mg monthly (N = 851) for 12 months. In this combined post-hoc analysis, a subset of higher risk subjects was identified, and the percentage changes from baseline in BMD and serum C-telopeptide of type I collagen (sCTX-1) were assessed.

RESULTS

In the overall population, denosumab was associated with greater gains in BMD at 12 months than monthly oral BP at the total hip, femoral neck, and lumbar spine (p < 0.0001 for all). In higher risk subjects, denosumab led to greater gains in BMD than oral BPs at the total hip (2.2 vs 0.8 %), femoral neck (1.8 vs 0.3 %), and lumbar spine (3.7 vs 1.4 %) (p < 0.0001 for all). Denosumab also led to greater decreases in sCTX-1 in the overall population and higher risk subjects at months 1 and 6 (p < 0.0001 for both). Adverse events and serious adverse events were generally similar between treatment groups.

CONCLUSIONS

Transitioning to denosumab was well tolerated and more effective in increasing BMD and reducing bone turnover than cycling to a monthly oral BP treatment in subjects who remained at higher fracture risk despite suboptimal BP treatment.

Romosozumab in postmenopausal women with low bone mineral density

BACKGROUND

Sclerostin is an osteocyte-derived inhibitor of osteoblast activity. The monoclonal antibody romosozumab binds to sclerostin and increases bone formation.

METHODS

In a phase 2, multicenter, international, randomized, placebo-controlled, parallel-group, eight-group study, we evaluated the efficacy and safety of romosozumab over a 12-month period in 419 postmenopausal women, 55 to 85 years of age, who had low bone mineral density (a T score of -2.0 or less at the lumbar spine, total hip, or femoral neck and -3.5 or more at each of the three sites). Participants were randomly assigned to receive subcutaneous romosozumab monthly (at a dose of 70 mg, 140 mg, or 210 mg) or every 3 months (140 mg or 210 mg), subcutaneous placebo, or an open-label active comparator--oral alendronate (70 mg weekly) or subcutaneous teriparatide (20 μg daily). The primary end point was the percentage change from baseline in bone mineral density at the lumbar spine at 12 months. Secondary end points included percentage changes in bone mineral density at other sites and in markers of bone turnover.

RESULTS

All dose levels of romosozumab were associated with significant increases in bone mineral density at the lumbar spine, including an increase of 11.3% with the 210-mg monthly dose, as compared with a decrease of 0.1% with placebo and increases of 4.1% with alendronate and 7.1% with teriparatide. Romosozumab was also associated with large increases in bone mineral density at the total hip and femoral neck, as well as transitory increases in bone-formation markers and sustained decreases in a bone-resorption marker. Except for mild, generally nonrecurring injection-site reactions with romosozumab, adverse events were similar among groups.

CONCLUSIONS

In postmenopausal women with low bone mass, romosozumab was associated with increased bone mineral density and bone formation and with decreased bone resorption. (Funded by Amgen and UCB Pharma; ClinicalTrials.gov number, NCT00896532.).

Effects of pioglitazone on bone in postmenopausal women with impaired fasting glucose or impaired glucose tolerance: a randomized, double-blind, placebo-controlled study

CONTEXT

Meta-analyses of clinical studies have suggested an increased incidence of peripheral fractures in postmenopausal women with type 2 diabetes mellitus taking pioglitazone. The mechanism behind this apparent increase is unknown.

OBJECTIVE

The objective of the study was to examine the effects of pioglitazone on bone mineral density (BMD) and turnover.

DESIGN AND SETTING

Twenty-five sites (in the United States) enrolled participants in this randomized, double-blind, placebo-controlled study.

PARTICIPANTS

Postmenopausal women (n = 156) with impaired fasting glucose or impaired glucose tolerance participated in the study.

INTERVENTIONS

The intervention consisted of pioglitazone 30 mg/d (n = 78) or placebo (n = 78), increased to 45 mg/d after 1 month, for 12 months of treatment total, followed by 6 months of washout/follow-up.

MAIN OUTCOME MEASURES

Percentage changes from baseline to month 12 and from month 12 to month18 in BMD in total proximal femur (primary end point), total body, femoral neck, lumbar spine, and radius were measured.

RESULTS

Least squares mean changes from baseline to month 12 in total proximal femur BMD were -0.69% for pioglitazone and -0.14% for placebo (P = .170). No statistically significant between-group differences were observed for any BMD or bone remodeling marker end point. We observed improved glycemic control and insulin sensitivity with pioglitazone treatment. In addition, pioglitazone appeared to increase body fat, which may affect bone density measurements, especially in the lumbar spine. One pioglitazone-treated and three placebo-treated women experienced confirmed fractures. Over 18 months, one pioglitazone-treated (1.3%) and eight placebo-treated women (10.3%) developed overt type 2 diabetes mellitus. The pattern and incidence of adverse events with pioglitazone were consistent with clinical experience with thiazolidinediones.

CONCLUSIONS

Maximal-dose pioglitazone had no effects on BMD or bone turnover, while improving glycemic control as expected, in postmenopausal women with impaired fasting glucose or impaired glucose tolerance.

The effect of three or six years of denosumab exposure in women with postmenopausal osteoporosis: results from the FREEDOM extension

CONTEXT

The Fracture Reduction Evaluation of Denosumab in Osteoporosis Every 6 Months (FREEDOM) extension is evaluating the long-term efficacy and safety of denosumab for up to 10 years.

OBJECTIVE

The objective of the study was to report results from the first 3 years of the extension, representing up to 6 years of denosumab exposure.

DESIGN, SETTING, AND PARTICIPANTS

This was a multicenter, international, open-label study of 4550 women.

INTERVENTION

Women from the FREEDOM denosumab group received 3 more years of denosumab for a total of 6 years (long-term) and women from the FREEDOM placebo group received 3 years of denosumab (crossover).

MAIN OUTCOME MEASURES

Bone turnover markers (BTMs), bone mineral density (BMD), fracture, and safety data are reported.

RESULTS

Reductions in BTMs were maintained (long-term) or achieved rapidly (crossover) after denosumab administration. In the long-term group, BMD further increased for cumulative 6-year gains of 15.2% (lumbar spine) and 7.5% (total hip). During the first 3 years of denosumab treatment, the crossover group had significant gains in lumbar spine (9.4%) and total hip (4.8%) BMD, similar to the long-term group during the 3-year FREEDOM trial. In the long-term group, fracture incidences remained low and below the rates projected for a virtual placebo cohort. In the crossover group, 3-year incidences of new vertebral and nonvertebral fractures were similar to those of the FREEDOM denosumab group. Incidence rates of adverse events did not increase over time. Six participants had events of osteonecrosis of the jaw confirmed by adjudication. One participant had a fracture adjudicated as consistent with atypical femoral fracture.

CONCLUSION

Denosumab treatment for 6 years remained well tolerated, maintained reduced bone turnover, and continued to increase BMD. Fracture incidence remained low.

Hypocalcemia in patients with metastatic bone disease receiving denosumab

9628

Background: Patients (pts) with metastatic bone disease (MBD) are at risk of skeletal-related events (SREs). Potent antiresorptives reduce the risk of SREs, by inhibiting cancer-induced bone destruction, which also reduces release of skeletal calcium (Ca) into the bloodstream. Hypocalcemia (hypoCa) may occur if Ca and vit D intake is inadequate while taking antiresorptive agents. A combined analysis of 3 phase III trials in pts with MBD showed denosumab (DMAb) was superior to zoledronic acid (ZA) in preventing SREs. The overall safety profiles were similar; hypoCa was more common with DMAb (9.6%) than ZA (5.0%). Characteristics of hypoCa events in DMAb pts in these clinical trials and from post marketing adverse event (AE) reports are presented. Methods: Pts with solid tumors or multiple myeloma and MBD were randomized (1:1) to DMAb 120 mg SC or ZA 4 mg IV (adjusted for renal function) every 4 weeks (Q4W). Pts were advised to take daily Ca (≥ 500 mg) and vit D (≥ 400 IU); intake was collected by pt report. Albumin-corrected serum Ca was measured Q4W by central lab. HypoCa events were collected as decreases in serum Ca per central lab and investigator-reported AEs. Post marketing data from spontaneous reports of hypoCa to the sponsor's global safety department (AGS) were reviewed. Results: In the 3 trials, 2841 pts received DMAb and 2836 pts received ZA. The median Ca levels for both treatment groups were similar over time. Among DMAb pts, hypoCa was most common within 6 months of starting treatment and was more common in pts who did not report use of Ca and vit D vs those who did (15.8% vs 8.7%). Grade 3 or 4 (< 7 mg/dL; < 1.75 mmol/L) decreases in serum Ca were reported in 3.1% of DMAb pts and 1.3% of ZA pts. No fatal cases of hypoCa were reported in the trials. From May to Nov 2012, 37 cases of severe symptomatic hypoCa (seizures, tetany, prolonged QTc, altered mental state) were reported to AGS; fatal outcomes were reported for 3 other pts with advanced cancers and various comorbidities. Conclusions: HypoCa is a known risk with antiresorptive therapy, including DMAb 120 mg. HypoCa occurred less often in pts who reported taking Ca and vit D. HypoCa should be corrected prior to starting DMAb and Ca monitored during treatment. Pts should take adequate Ca and vit D while receiving DMAb. Clinical trial information: NCT00321464, NCT00321620, and NCT00330759.

Improved adherence with PTH(1-84) in an extension trial for 24 months results in enhanced BMD gains in the treatment of postmenopausal women with osteoporosis

The purpose of this study is to examine the effect of PTH(1-84) treatment over 24 months followed by 12 months discontinuation on BMD, bone turnover markers, fractures and the impact of adherence on efficacy.

INTRODUCTION

There is limited information about the effect of PTH(1-84) after 18 months and limited data about the impact of compliance on response to anabolic therapy.

METHODS

Seven hundred and eighty-one subjects who received active PTH(1-84) in the Treatment of Osteoporosis with Parathyroid hormone trial for approximately 18 months were entered into a 6-month open-label extension. Thereafter, they were followed for 12 additional months after discontinuation of treatment. Endpoints examined included changes in BMD and biochemical markers.

RESULTS

PTH(1-84) treatment over 24 months increased BMD at the lumbar spine by 6.8% above baseline (p<0.05).The total corresponding BMD increases at the hip and femoral neck were 1.1 and 2.2% above baseline. Larger increases in spine BMD were observed in participants with ≥80% adherence to daily injections of PTH(1-84) (8.3% in adherent vs 4.9% in poorly adherent patients). Total hip BMD gains were 1.7% in adherent vs 0.6% in poorly adherent participants. Markers of bone turnover (BSAP and NTx) peaked 6 months after starting PTH(1-84) treatment and declined slowly but remained above baseline at 24 months. After discontinuation of PTH(1-84) treatment (at 24 months), bone turnover markers returned to near baseline levels by 30 months. The adherent group sustained significantly fewer fractures than the poorly adherent group.

CONCLUSIONS

PTH(1-84) treatment over 24 months results in continued increases in lumbar spine BMD. Adherence to treatment with PTH(1-84) for up to 24 months is also associated with greater efficacy.

A randomized, placebo-controlled study of the effects of denosumab for the treatment of men with low bone mineral density

CONTEXT

Men with low bone mineral density (BMD) were treated with denosumab.

OBJECTIVE

Our objective was to investigate the effects of denosumab compared with placebo in men with low BMD after 1 yr of treatment.

DESIGN, SUBJECTS, AND INTERVENTION

This was a placebo-controlled, phase 3 study to investigate the efficacy and safety of denosumab 60 mg every 6 months vs. placebo in men with low BMD.

MAIN OUTCOME MEASURE

The primary endpoint was the percent change from baseline in lumbar spine (LS) BMD at month 12.

RESULTS

Of the 242 randomized subjects (mean age 65 yr), 228 (94.2%) completed 1 yr of denosumab therapy. After 12 months, denosumab resulted in BMD increases of 5.7% at the LS, 2.4% at the total hip, 2.1% at the femoral neck, 3.1% at the trochanter, and 0.6% at the one third radius (adjusted P ≤ 0.0144 for BMD percent differences at all sites compared with placebo). Sensitivity analyses done by controlling for baseline covariates (such as baseline testosterone levels, BMD T-scores, and 10-yr osteoporotic fracture risk) demonstrated that the results of the primary endpoint were robust. Subgroup analyses indicate that treatment with denosumab was effective across a spectrum of clinical situations. Treatment with denosumab significantly reduced serum CTX levels at d 15 (adjusted P < 0.0001). The incidence of adverse events was similar between groups.

CONCLUSIONS

One year of denosumab therapy in men with low BMD was well tolerated and resulted in a reduction in bone resorption and significant increases in BMD at all skeletal sites assessed.

A single-dose study of denosumab in patients with various degrees of renal impairment

This 16-week study evaluated pharmacokinetics and pharmacodynamics of denosumab in 55 subjects with renal function ranging from normal to dialysis-dependent kidney failure. Participants received a single 60-mg subcutaneous dose of denosumab. Kidney function groups were based on calculations using the Cockcroft-Gault equation and U.S. Food and Drug Administration (FDA) guidance in place when the study was designed. Renal function did not have a significant effect on denosumab pharmacokinetics or pharmacodynamics. These findings suggest denosumab dose adjustment based on glomerular filtration rate is not required. Rapid decreases in serum C-telopeptide in all groups were sustained throughout the study. The most common adverse events were hypocalcemia (15%), pain in extremity (15%), and nausea (11%). Most adverse events were mild to moderate in severity. Calcium and vitamin D supplementation was not initially required by the study protocol, but was added during the trial. No subject who received adequate calcium and vitamin D supplementation became hypocalcemic. Seven subjects had nadir serum calcium concentrations between 7.5 and <8.0 mg/dL (1.9 and <2.0 mmol/L), and 5 subjects (4 with advanced renal disease) had nadir serum calcium <7.5 mg/dL (<1.9 mmol/L). Two subjects (1 symptomatic, 1 asymptomatic) were hospitalized for intravenous calcium gluconate treatment. At the recommended dose, denosumab is a useful therapeutic option for patients with impaired renal function. Supplementation of calcium and vitamin D is strongly recommended when patients initiate denosumab therapy, particularly in patients with reduced renal function.

Five years of denosumab exposure in women with postmenopausal osteoporosis: results from the first two years of the FREEDOM extension

The 3-year FREEDOM trial assessed the efficacy and safety of 60 mg denosumab every 6 months for the treatment of postmenopausal women with osteoporosis. Participants who completed the FREEDOM trial were eligible to enter an extension to continue the evaluation of denosumab efficacy and safety for up to 10 years. For the extension results presented here, women from the FREEDOM denosumab group had 2 more years of denosumab treatment (long-term group) and those from the FREEDOM placebo group had 2 years of denosumab exposure (cross-over group). We report results for bone turnover markers (BTMs), bone mineral density (BMD), fracture rates, and safety. A total of 4550 women enrolled in the extension (2343 long-term; 2207 cross-over). Reductions in BTMs were maintained (long-term group) or occurred rapidly (cross-over group) following denosumab administration. In the long-term group, lumbar spine and total hip BMD increased further, resulting in 5-year gains of 13.7% and 7.0%, respectively. In the cross-over group, BMD increased at the lumbar spine (7.7%) and total hip (4.0%) during the 2-year denosumab treatment. Yearly fracture incidences for both groups were below rates observed in the FREEDOM placebo group and below rates projected for a "virtual untreated twin" cohort. Adverse events did not increase with long-term denosumab administration. Two adverse events in the cross-over group were adjudicated as consistent with osteonecrosis of the jaw. Five-year denosumab treatment of women with postmenopausal osteoporosis maintained BTM reduction and increased BMD, and was associated with low fracture rates and a favorable risk/benefit profile.

Alendronate and atrial fibrillation: a meta-analysis of randomized placebo-controlled clinical trials

In this meta-analysis of all Merck-conducted, placebo-controlled clinical trials of alendronate, the occurrence of AF was uncommon, with most studies reporting two or fewer events. Across all studies, no clear association between overall bisphosphonate exposure and the rate of serious or non-serious AF was observed.

INTRODUCTION

To explore the incidence of atrial fibrillation (AF) and other cardiovascular endpoints in clinical trials of alendronate.

METHODS

All double-blind, placebo-controlled studies of alendronate 5, 10, or 20 mg daily, 35 mg once-weekly, 35 mg twice-weekly, and 70 mg once-weekly of at least 3 months duration conducted by Merck were included in this meta-analysis. The primary method of analysis was exact Poisson regression. Estimated relative risk (RR) of alendronate versus placebo and the associated 95% confidence interval was derived from a model that included number of episodes with factors for treatment group and study and an offset parameter for number of person-years on study.

RESULTS

Of 41 studies considered, 32 met all criteria for inclusion in the analysis (participants-9,518 alendronate, 7,773 placebo). Estimated RR for all AF events was 1.16 (95% CI = 0.87, 1.55; p = 0.33). Most trials had two or fewer AF events. The RR of AF classified as a serious adverse event was 1.25 (95% CI = 0.82, 1.93; p = 0.33), but became 0.97 (95% CI = 0.51, 1.85) when the clinical fracture cohort of the Fracture Intervention Trial was excluded, indicating that results were driven by events in that study. Estimated RRs for other cardiovascular endpoints were less than 1.

CONCLUSIONS

The incidence of atrial fibrillation was low in Merck clinical trials of alendronate and was not significantly increased in any single trial nor in the meta-analysis. Based on this analysis, alendronate use does not appear to be associated with an increased risk of atrial fibrillation.

Effect of denosumab treatment on the risk of fractures in subgroups of women with postmenopausal osteoporosis

Denosumab reduces the risk of new vertebral and nonvertebral fractures. Previous trials suggest that the efficacy of antiresorptives on fractures might differ by patients' characteristics, such as age, bone mineral density (BMD), and fracture history. In the FREEDOM study, 7808 women aged 60 to 90 years with osteoporosis were randomly assigned to receive subcutaneous injections of denosumab (60 mg) or placebo every 6 months for 3 years. New vertebral and nonvertebral fractures were radiologically confirmed. Subgroup analyses described in this article were prospectively planned before study unblinding to evaluate the effect of denosumab on new vertebral and nonvertebral fractures across various subgroups. Compared with placebo, denosumab decreased the risk of new vertebral fractures in the overall study population over 3 years. This effect did not significantly differ for any of the nine subgroups analyzed (p > 0.09 for all potential interactions). Denosumab also reduced all nonvertebral fractures by 20% in the full study cohort over 3 years. This risk reduction was statistically significant in women with a baseline femoral neck BMD T-score ≤ -2.5 but not in those with a T-score > -2.5; in those with a body mass index (BMI) < 25 kg/m(2) but not ≥ 25 kg/m(2); and in those without but not with a prevalent vertebral fracture. These differential treatment effects were not explained by differences in BMD responses to denosumab. Denosumab 60 mg administered every 6 months for 3 years in women with osteoporosis reduced the risk of new vertebral fractures to a similar degree in all subgroups. The effect of denosumab on nonvertebral fracture risk differed by femoral neck BMD, BMI, and prevalent vertebral fracture at baseline.

The effects of ronacaleret, a calcium-sensing receptor antagonist, on bone mineral density and biochemical markers of bone turnover in postmenopausal women with low bone mineral density

CONTEXT

Ronacaleret, a calcium-sensing receptor antagonist that stimulates PTH release from the parathyroid glands, was evaluated as an oral osteoanabolic agent for the treatment of osteoporosis.

OBJECTIVE

Our objective was to compare the effects of ronacaleret, teriparatide, and alendronate on bone mineral density (BMD) and markers of bone turnover.

DESIGN AND SETTING

In this randomized, placebo-controlled, dose-ranging trial, spine and hip BMD were assessed by dual-energy x-ray absorptiometry and bone turnover markers were measured.

PATIENTS

Patients included 569 postmenopausal women with low BMD.

INTERVENTIONS

Subjects were offered open-label 20 μg teriparatide sc once daily or were randomized to 100, 200, 300, or 400 mg oral ronacaleret once daily, 70 mg alendronate once weekly, or placebo and were followed for up to 12 months.

MAIN OUTCOME MEASURE

Percentage change from baseline in lumbar spine BMD was assessed at month 12.

RESULTS

With ronacaleret, the increases in lumbar spine BMD at 12 months (0.3-1.6%) were significantly lower than those attained with teriparatide (9.1%) or alendronate (4.5%). There were small decreases in total hip, femoral neck, and trochanter BMD at month 12 with ronacaleret compared with increases in the teriparatide and alendronate arms. Bone turnover markers increased in the ronacaleret and teriparatide arms and decreased in the alendronate arm. PTH elevations with ronacaleret were prolonged relative to those previously reported with teriparatide.

CONCLUSION

The densitometric findings in the context of prolonged PTH elevation and increased bone turnover suggest ronacaleret induces mild hyperparathyroidism. Ronacaleret only modestly increased lumbar spine BMD and decreased BMD at hip sites.

Effects of denosumab treatment and discontinuation on bone mineral density and bone turnover markers in postmenopausal women with low bone mass

CONTEXT

Denosumab treatment for 24 months increased bone mineral density (BMD) and reduced bone turnover markers (BTM) in postmenopausal women.

OBJECTIVE

The aim was to determine the effects of prior denosumab or placebo injections on BMD, BTM, and safety over 24 months after treatment discontinuation.

DESIGN

We conducted an off-treatment extension of a phase 3, randomized, double-blind, parallel-group study.

PARTICIPANTS

A total of 256 postmenopausal women with a mean age of 59 yr and a mean lumbar spine T-score of -1.61 at randomization participated in the study.

INTERVENTIONS

Participants received placebo or 60 mg denosumab every 6 months for 24 months, followed by 24 months off treatment.

MAIN OUTCOME MEASURES

We measured the percentage changes in BMD and BTM, and evaluated safety.

RESULTS

Of the 256 participants enrolled in the posttreatment phase, 87% completed the study. During 24 months of denosumab treatment, BMD increased (lumbar spine, 6.4%; total hip, 3.6%; 1/3 radius, 1.4%), and BTM decreased (serum C-terminal telopeptide of type 1 collagen, 63%; and N-terminal propeptide of type 1 procollagen, 47%), compared with placebo. After discontinuation, BMD declined, but the previously treated denosumab group maintained higher BMD than the previously treated placebo group at these sites (P ≤ 0.05). Final BMD at month 48 strongly correlated with month 0 BMD. After denosumab discontinuation, BTM increased above baseline within 3 months (serum C-terminal telopeptide of type 1 collagen) or 6 months (N-terminal propeptide of type 1 procollagen) and returned to baseline by month 48. Adverse event rates during the off-treatment phase were similar between groups.

CONCLUSIONS

In postmenopausal women with low BMD, the effects of 60 mg denosumab treatment for 24 months on BMD and BTM are reversible upon discontinuation, reflecting its biological mechanism of action. Residual BMD measurements remained above those of the group previously treated with placebo.

Odanacatib in the treatment of postmenopausal women with low bone mineral density: three-year continued therapy and resolution of effect

The selective cathepsin K inhibitor odanacatib (ODN) progressively increased bone mineral density (BMD) and decreased bone-resorption markers during 2 years of treatment in postmenopausal women with low BMD. A 1-year extension study further assessed ODN efficacy and safety and the effects of discontinuing therapy. In the base study, postmenopausal women with BMD T-scores between -2.0 and -3.5 at the lumbar spine or femur received placebo or ODN 3, 10, 25, or 50 mg weekly. After 2 years, patients (n = 189) were rerandomized to ODN 50 mg weekly or placebo for an additional year. Endpoints included BMD at the lumbar spine (primary), total hip, and hip subregions; levels of bone turnover markers; and safety assessments. Continued treatment with 50 mg of ODN for 3 years produced significant increases from baseline and from year 2 in BMD at the spine (7.9% and 2.3%) and total hip (5.8% and 2.4%). Urine cross-linked N-telopeptide of type I collagen (NTx) remained suppressed at year 3 (-50.5%), but bone-specific alkaline phosphatase (BSAP) was relatively unchanged from baseline. Treatment discontinuation resulted in bone loss at all sites, but BMD remained at or above baseline. After ODN discontinuation at month 24, bone turnover markers increased transiently above baseline, but this increase largely resolved by month 36. There were similar overall adverse-event rates in both treatment groups. It is concluded that 3 years of ODN treatment resulted in progressive increases in BMD and was generally well tolerated. Bone-resorption markers remained suppressed, whereas bone-formation markers returned to near baseline. ODN effects were reversible: bone resorption increased transiently and BMD decreased following treatment discontinuation.

Denosumab improves density and strength parameters as measured by QCT of the radius in postmenopausal women with low bone mineral density

BACKGROUND

Bone strength is determined by both cortical and trabecular bone compartments and can be evaluated radiologically through measurement of bone density and geometry. Quantitative computed tomography (QCT) separately assesses cortical and trabecular bone reliably at various sites, including the distal radius where there is a gradation of cortical and trabecular bone. We evaluated the effect of denosumab, a fully human monoclonal antibody that inhibits RANK ligand, on distal radius QCT in women with low bone mass to assess the impact of this novel therapy separately on trabecular and cortical bone.

METHODS

Postmenopausal women (n=332) with spine areal bone mineral density (BMD) T-scores between -1.0 and -2.5 received denosumab 60 mg or placebo every 6 months during the 24-month study. QCT measurements along the distal radius were made using a whole-body computed tomography scanner and were used to determine the percentage change from baseline in volumetric BMD; volumetric bone mineral content (BMC); cortical thickness; volume; circumference; and density-weighted polar moment of inertia (PMI), a derived index of bone strength.

RESULTS

Denosumab treatment significantly increased total BMD and BMC along the radius (proximal, distal, and ultradistal sections). At 24 months, the ultradistal region had the greatest percentage increase in total BMD (4.7% [95% CI, 3.6-5.7]; P<0.001) and total BMC (5.7% [95% CI, 4.8-6.6]; P<0.001) over placebo. When cortical and trabecular bone at the proximal and distal regions were separately assessed, cortical bone had significant (P<0.001) increases in BMD, BMC, and thickness, and trabecular bone had a significant increase in BMD relative to placebo (P<0.05). Bone strength, estimated by density-weighted PMI, significantly increased compared with placebo after 6 months of treatment, with the largest percentage increase occurring at 24 months in the ultradistal region (6.6% [95% CI, 5.6-7.6]; P<0.0001).

CONCLUSIONS

QCT measurements demonstrated that denosumab significantly increased BMD, BMC, and PMI along the radius over 24 months. Additionally, denosumab prevented the decrease in QCT-measured cortical thickness observed in the placebo group. These data extend the evidence from previous dual-energy X-ray absorptiometry studies for a positive effect of denosumab on both the cortical and trabecular bone compartments and propose a possible mechanism for the reduction in fracture risk achieved with denosumab therapy.

Preference and satisfaction with a 6-month subcutaneous injection versus a weekly tablet for treatment of low bone mass

The Preference and Satisfaction Questionnaire (PSQ) compares patient preference and satisfaction between a 6-month subcutaneous injection and weekly oral tablet for treatment of bone loss. Patients preferred and were more satisfied with a treatment that was administered less frequently, suggesting the acceptability of the 6-month injection for treatment of bone loss.

INTRODUCTION

The PSQ compares patient preference and satisfaction between a 6-month subcutaneous injection and a weekly oral tablet for treatment of bone loss.

METHODS

Postmenopausal women with low bone mass who enrolled in two separate randomized phase 3 double-blind, double-dummy studies received a 6-month subcutaneous denosumab injection (60 mg) plus a weekly oral placebo or a weekly alendronate tablet (70 mg) plus a 6-month subcutaneous placebo injection. After 12 months, patients completed the PSQ to rate their preference, satisfaction, and degree of bother with each regimen.

RESULTS

Most enrolled patients (1,583 out of 1,693; 93.5%) answered >or=1 item of the PSQ. Significantly more patients preferred and were more satisfied with the 6-month injection versus the weekly tablet (P < 0.001). More patients reported no bother with the 6-month injection (90%) than the weekly tablet (62%).

CONCLUSION

Patients preferred, were more satisfied, and less bothered with a 6-month injection regimen for osteoporosis.

Four-month treatment with GLP-2 significantly increases hip BMD: a randomized, placebo-controlled, dose-ranging study in postmenopausal women with low BMD

We have previously shown that repeated dosing of glucagon-like peptide-2 (GLP-2) at 10 p.m. in postmenopausal women for 14 days results in a dose-dependent decrease in the nocturnal bone resorption, as assessed by s-CTX. In contrast, bone formation, as assessed by serum osteocalcin, appeared to be unaffected by treatment with exogenous GLP-2, at least over 14 days. The present study extends the observation period to four months. The study was a double-blind placebo-controlled dose-ranging trial comparing three different doses of GLP-2 (0.4 mg, 1.6 mg and 3.2 mg GLP-2, administered nightly) against a saline control injection. We examined safety and tolerability, and the effects on biochemical markers of bone turnover and the effect on bone mineral density. Injection of 0.4 mg, 1.6 mg and 3.2 mg GLP-2 resulted in similar reduction in the nocturnal rise of s-CTX, at Treatment Day 120 the mean difference to placebo was approximately -150%*h at AUC(0-10H) (P<0.01). Osteocalcin levels were unaffected in the 10-hour period after injection indicating that injections of 0.4 mg, 1.6 mg and 3.2 mg GLP-2 do not exert any acute stimulatory or inhibitory effect on bone formation. Treatment with GLP-2 resulted in a significant dose-dependent increase in total hip BMD over the course of the study that for the 3.2 mg GLP-2 group reached 1.1% (P=0.007) from baseline. The overall rates of adverse events in the 4 treatment groups were similar and there were no signs of tachyphylaxis or antibodies against GLP-2. The results indicate that GLP-2 produces a substantial decrease in bone resorption without suppression of bone formation thereby changing the bone remodeling balance in favor of bone formation, particularly at the hip.

A 24-month subgroup analysis of the effect of denosumab on bone mineral density in women with breast cancer undergoing aromatase inhibitor therapy

Abstract #2106

Background: Accelerated bone loss and fracture risk are expected consequences of adjuvant aromatase inhibitor (AI) therapy. We previously showed that denosumab, a fully human monoclonal antibody that inhibits RANK ligand (RANKL), significantly increased bone mineral density (BMD) at the lumbar spine and at all measured skeletal sites at 12 months compared with placebo in women with breast cancer undergoing adjuvant AI therapy (Ellis et al, 2007 SABCS). In this analysis, we assessed covariates that may influence treatment effects on BMD at the lumbar spine, total hip, femoral neck, and 1/3 radius at 24 months.&#x2028; Methods: Adult patients (pts) with hormone receptor-positive breast cancer, who had evidence of low bone mass and were receiving adjuvant AI therapy, were enrolled in this randomized, double-blind, placebo-controlled, phase 3 study. Pts were stratified according to length of previous AI therapy (≤ 6 vs &gt; 6 months) and randomly assigned to receive, together with calcium and vitamin D, placebo (n=125) or denosumab 60 mg (n=127) subcutaneously every 6 months for 4 doses. Subgroup analysis was conducted using analysis of covariance and adjusted for treatment, stratification factor, baseline BMD value, densitometer type, and baseline BMD value-by-densitometer-type interaction.&#x2028; Results: At 24 months, greater increases in BMD were seen at all measured skeletal sites (both trabecular and cortical bone) for denosumab compared with placebo, regardless of the subgroup (table). Adverse events (AEs) occurred at a similar rate in both groups (91% denosumab, 90% placebo).&#x2028; Conclusion: In pts with breast cancer undergoing adjuvant AI therapy, twice-yearly denosumab treatment showed consistent increases in BMD across the skeleton at 24 months compared with placebo, regardless of subgroups.&#x2028; &#x2028;

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 2106.

Randomized trial of denosumab in patients receiving adjuvant aromatase inhibitors for nonmetastatic breast cancer

PURPOSE

Adjuvant aromatase inhibitor therapy is well established in postmenopausal women with hormone receptor-positive breast cancer, but such therapy is complicated by accelerated bone loss and increased fracture risk. We investigated the ability of denosumab, a fully human monoclonal antibody against receptor activator of nuclear factor-kappaB ligand, to protect against aromatase inhibitor-induced bone loss.

PATIENTS AND METHODS

Eligible women with hormone receptor-positive nonmetastatic breast cancer treated with adjuvant aromatase inhibitor therapy were stratified by duration of aromatase inhibitor therapy (< or = 6 v > 6 months), received supplemental calcium and vitamin D, and were randomly assigned to receive placebo (n = 125) or subcutaneous denosumab 60 mg (n = 127) every 6 months. At enrollment, all patients were required to have evidence of low bone mass, excluding osteoporosis. The primary end point was percentage change from baseline at month 12 in lumbar spine bone mineral density (BMD).

RESULTS

At 12 and 24 months, lumbar spine BMD increased by 5.5% and 7.6%, respectively, in the denosumab group versus placebo (P < .0001 at both time points). Increases were observed as early as 1 month and were not influenced by duration of aromatase inhibitor therapy. Increases in BMD were also observed at the total hip, total body, femoral neck, and the predominantly cortical one-third radius. Bone turnover markers decreased with denosumab treatment. Overall incidence of treatment-emergent adverse events (AEs) was similar between treatment groups.

CONCLUSION

In women with nonmetastatic breast cancer and low bone mass who were receiving adjuvant aromatase inhibitor therapy, twice-yearly administration of denosumab led to significant increases in BMD over 24 months at trabecular and cortical bone, with overall AE rates similar to those of placebo.

Effects of denosumab on bone mineral density and bone turnover in postmenopausal women

CONTEXT

Denosumab is an investigational fully human monoclonal antibody against receptor activator of nuclear factor-kappaB ligand, a mediator of osteoclastogenesis and osteoclast survival.

OBJECTIVE

This study evaluated the ability of denosumab to increase bone mineral density (BMD) and decrease bone turnover markers (BTMs) in early and later postmenopausal women with low BMD.

DESIGN AND SETTING

This 2-yr randomized, double-blind, placebo-controlled study was conducted in North America.

PARTICIPANTS

Subjects included 332 postmenopausal women with lumbar spine BMD T-scores between -1.0 and -2.5.

INTERVENTIONS

SUBJECTS were randomly assigned to receive denosumab sc, 60 mg every 6 months, or placebo. Randomization was stratified by time since onset of menopause (< or =5 yr or > 5 yr).

MAIN OUTCOME MEASURES

The primary end point was the percent change in lumbar spine BMD by dual-energy x-ray absorptiometry at 24 months. Additional end points were percent change in volumetric BMD of the distal radius by quantitative computed tomography; percent change in BMD by dual-energy x-ray absorptiometry for the total hip, one-third radius, and total body; hip structural analysis; percent change in BTMs; and safety.

RESULTS

Denosumab significantly increased lumbar spine BMD, compared with placebo at 24 months (6.5 vs. -0.6%; P<0.0001) with similar results for both strata. Denosumab also produced significant increases in BMD at the total hip, one-third radius, and total body (P < 0.0001 vs. placebo); increased distal radius volumetric BMD (P < 0.01); improved hip structural analysis parameters; and significantly suppressed serum C-telopeptide, tartrate-resistant acid phosphatase-5b, and intact N-terminal propeptide of type 1 procollagen. The overall incidence of adverse events was similar between both study groups.

CONCLUSIONS

Twice-yearly denosumab increased BMD and decreased BTMs in early and later postmenopausal women.

Sequestosome 1 (SQSTM1) mutations in Paget's disease of bone from the United States

Paget's disease of bone (PDB) is a localized bone disease characterized by excessive bone resorption due to overactive osteoclasts. Seven genetic loci (PDB1-PDB7) have been reported for late-onset PDB. PDB3 is the only locus where a gene, sequestosome 1 (SQSTM1), has been identified. Mutations in SQSTM1 have been associated with both sporadic and hereditary PDB in different populations. However, the SQSTM1 mutation frequency in PDB patients from a more heterogeneous population has never been reported. To investigate this, we determined the frequency of mutations in patients from the United States. Blood was collected from sporadic and hereditary PDB patients in the United States. DNA was isolated from whole blood or from serum. The SQSTM1 sequence was determined for exons and intron/exon junctions from whole blood and serum. A total of 112 (39 hereditary, 73 sporadic) samples were collected. Eight mutations were found in hereditary PDB patients, for a mutation frequency of 20.5% (95% confidence interval [CI] 10.8-35.5%) and did not differ significantly from mutation rates observed in studies in Canada, Great Britain, and The Netherlands. No mutations were found in sporadic patients, for a frequency of 0% (95% CI 0.0-5.0%), which was statistically significantly lower than the mutation rates previously observed in populations from Australia (P = 0.009), Canada (P = 0.008), Great Britain (P = 0.02), and France (P = 0.04) but not compared to rates from Belgium, The Netherlands, and Italy. Four out of five families with the P392L mutation carried it on the H2 haplotype. Mutations in SQSTM1 seem to contribute to the pathogenesis of PDB in hereditary, but not sporadic, patients in the United States.